A pediatric dentist in Foster City has sued two people over negative comments about her practice that were posted on the review site Yelp, accusing them of libel.

The suit, filed in December in Santa Clara County Superior Court, asks for damages because of the posting, which complained about how Yvonne Wong treated a boy who visited her with cavities.

"I don't want these lies to be posted on the Web site about me," Wong said in an interview. "I'm not looking for money."

Wong said she had no choice but to also sue Yelp because the company refused to take the review down. In the posting, the author, "T.J.," complained that the boy was "light headed" after a filling because Wong gave him laughing gas, and that she used fillings containing mercury.

Wong's attorney, John Terbeek of San Leandro, said the boy's parents should have known about the mercury because they signed a consent form disclosing it. Terbeek said he probably will dismiss the charges against Yelp because he wasn't aware when he filed the suit that Web sites publishing third-party content are protected under U.S. law.

But Wong's case stands against Tai Jing and Jia Ma of Los Altos, the boy's parents. They could not be reached for comment.

This is the second lawsuit to emerge over negative reviews on Yelp, a popular Web site with headquarters in San Francisco.

On Friday, a San Francisco chiropractor, Steven Biegel, settled a libel case he had filed against a former patient, Christopher Norberg, after Norberg posted a review complaining about Biegel's billing practices.

Details of the settlement are confidential. Norberg replaced his post on Biegel's Yelp page with an apology that reads, "A misunderstanding between both parties led us to act out of hand. I chose to ignore Dr. Biegel's initial request to discuss my posting. In hindsight, I should have remained open to his concerns. Both Dr. Biegel and I strongly believe in a person's right to express their opinions in a public forum."

The apology is also posted at standforspeech.com, a Web site Norberg had created to raise funds for his defense.

Both men declined to discuss the case other than to say it has been settled to their mutual satisfaction. "This is an issue I want to put behind me," Biegel said.

Despite Wong's case, Yelp continues to stand by reviewers' rights to post negative reviews about businesses. Yelp does not allow businesses to publicly respond to reviews, although business owners can contact reviewers privately.

Wong said it never occurred to her to contact the boy's parents. "I would be very upset and would not know what to say to them," she said.

No Yelp user has ever been successfully sued, according to Yelp CEO Jeremy Stoppelman, who posted a blog entry about Biegel's case last week.

"Personally, I'm glad we live in a country where freedom of expression is so well protected," he wrote.

T.J. has since taken down all but one sentence of the review, although Wong's low one-star rating remains on Yelp. The full review also still turns up in a search on Google, as does Norberg's negative review of Biegel.

Norberg's lawyer, Michael Blacksburg, predicts more cases. "Yelp and other bulletin board sites ... need to think about how to protect the reviewer and reviewee from flame wars or potentially libelous statements," he said. "How do we culturally train our public to responsibly publish online?"